人民币数字转换成大写形式

运用了正则表达式的功能，除了可以正确的转换成人民币的大写形式以外，还可以判断输入的形式是否正确有效。

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">  
<html xmlns="http://www.w3.org/1999/xhtml" lang="gb2312">  
 <head>  
 <title>将人民币数字转换成大写形式</title>  
 <script language="jscript">  
function convertCurrency(currencyDigits) {  
// Constants:  
 var MAXIMUM_NUMBER = 99999999999.99;  
 // Predefine the radix characters and currency symbols for output:  
 var CN_ZERO = "零";  
 var CN_ONE = "壹";  
 var CN_TWO = "贰";  
 var CN_THREE = "叁";  
 var CN_FOUR = "肆";  
 var CN_FIVE = "伍";  
 var CN_SIX = "陆";  
 var CN_SEVEN = "柒";  
 var CN_EIGHT = "捌";  
 var CN_NINE = "玖";  
 var CN_TEN = "拾";  
 var CN_HUNDRED = "佰";  
 var CN_THOUSAND = "仟";  
 var CN_TEN_THOUSAND = "万";  
 var CN_HUNDRED_MILLION = "亿";  
 var CN_SYMBOL = "人民币";  
 var CN_DOLLAR = "元";  
 var CN_TEN_CENT = "角";  
 var CN_CENT = "分";  
 var CN_INTEGER = "整";  
   
// Variables:  
 var integral; // Represent integral part of digit number.  
 var decimal; // Represent decimal part of digit number.  
 var outputCharacters; // The output result.  
 var parts;  
 var digits, radices, bigRadices, decimals;  
 var zeroCount;  
 var i, p, d;  
 var quotient, modulus;  
   
// Validate input string:  
 currencyDigits = currencyDigits.toString();  
 if (currencyDigits == "") {  
 alert("Empty input!");  
 return "";  
 }  
 if (currencyDigits.match(/[^,.\d]/) != null) {  
 alert("Invalid characters in the input string!");  
 return "";  
 }  
 if ((currencyDigits).match(/^((\d{1,3}(,\d{3})*(.((\d{3},)*\d{1,3}))?)|(\d+(.\d+)?))$/) == null) {  
 alert("Illegal format of digit number!");  
 return "";  
 }  
   
// Normalize the format of input digits:  
 currencyDigits = currencyDigits.replace(/,/g, ""); // Remove comma delimiters.  
 currencyDigits = currencyDigits.replace(/^0+/, ""); // Trim zeros at the beginning.  
 // Assert the number is not greater than the maximum number.  
 if (Number(currencyDigits) > MAXIMUM_NUMBER) {  
 alert("Too large a number to convert!");  
 return "";  
 }  
   
// Process the coversion from currency digits to characters:  
 // Separate integral and decimal parts before processing coversion:  
 parts = currencyDigits.split(".");  
 if (parts.length > 1) {  
 integral = parts[0];  
 decimal = parts[1];  
 // Cut down redundant decimal digits that are after the second.  
 decimal = decimal.substr(0, 2);  
 }  
 else {  
 integral = parts[0];  
 decimal = "";  
 }  
 // Prepare the characters corresponding to the digits:  
 digits = new Array(CN_ZERO, CN_ONE, CN_TWO, CN_THREE, CN_FOUR, CN_FIVE, CN_SIX, CN_SEVEN, CN_EIGHT, CN_NINE);  
 radices = new Array("", CN_TEN, CN_HUNDRED, CN_THOUSAND);  
 bigRadices = new Array("", CN_TEN_THOUSAND, CN_HUNDRED_MILLION);  
 decimals = new Array(CN_TEN_CENT, CN_CENT);  
 // Start processing:  
 outputCharacters = "";  
 // Process integral part if it is larger than 0:  
 if (Number(integral) > 0) {  
 zeroCount = 0;  
 for (i = 0; i < integral.length; i++) {  
 p = integral.length - i - 1;  
 d = integral.substr(i, 1);  
 quotient = p / 4;  
 modulus = p % 4;  
 if (d == "0") {  
 zeroCount++;  
 }  
 else {  
 if (zeroCount > 0)  
 {  
 outputCharacters += digits[0];  
 }  
 zeroCount = 0;  
 outputCharacters += digits[Number(d)] + radices[modulus];  
 }  
 if (modulus == 0 && zeroCount < 4) {  
 outputCharacters += bigRadices[quotient];  
 }  
 }  
 outputCharacters += CN_DOLLAR;  
 }  
 // Process decimal part if there is:  
 if (decimal != "") {  
 for (i = 0; i < decimal.length; i++) {  
 d = decimal.substr(i, 1);  
 if (d != "0") {  
 outputCharacters += digits[Number(d)] + decimals[i];  
 }  
 }  
 }  
 // Confirm and return the final output string:  
 if (outputCharacters == "") {  
 outputCharacters = CN_ZERO + CN_DOLLAR;  
 }  
 if (decimal == "") {  
 outputCharacters += CN_INTEGER;  
 }  
 outputCharacters = CN_SYMBOL + outputCharacters;  
 return outputCharacters;  
}  
 </script>  
 </head>  
 <body>  
 <input id="Digits" type="text" name="Digits" size="20" />  
 <input id="Convert" type="button" value="Convert" name="Convert" onclick="Result.value = convertCurrency(Digits.value);" />  
 <input id="Result" type="text" name="Result" size="60" />  
</body>  
</html>

[Ctrl+A 全选注:如需引入外部Js需刷新才能执行]